The ARCO 5384 Left-Hand Starter Motor is designed specifically for Mercury Racing and Mariner Racing two-stroke V6 outboards equipped with left-hand (LH) lightweight flywheel ring gears.
This starter is engineered for the unique starting requirements of Mercury's counter-rotating racing engines and is a direct replacement for Mercury OEM 50-60594T01, 50-60594A1, and 50-60594A.
Unlike production Mercury outboard starters, the ARCO 5384 utilizes a 10-tooth clockwise (CW) Bendix drive designed exclusively for Mercury Racing left-hand flywheel assemblies. It is not interchangeable with the common 8-tooth or 9-tooth starters used on standard production engines.
Designed for Mercury Racing Competition Engines
This starter fits Mercury Racing 2.0L, 2.4L, and 2.5L V6 engines manufactured from 1976 through 2005 that utilize left-hand (counter-rotating) lightweight flywheel ring gears. These engines are commonly found in professional tunnel boat racing, Formula racing, and other sanctioned competition classes where left-hand engine rotation is required.
Applications include the legendary SST-120, SST-140, Champ, Formula One (F1), and S3000 racing outboards, along with numerous custom Mercury Racing powerheads equipped with OEM or aftermarket billet left-hand flywheels.
Whether powering an APBA Formula boat, UIM tunnel hull, OPC race boat, or a vintage Mercury Racing restoration, the ARCO 5384 provides the proper starter engagement required for these specialized racing engines.
Precision 10-Tooth Bendix Drive
The ARCO 5384 is equipped with the correct 10-tooth starter pinion gear, engineered specifically to mesh with Mercury Racing left-hand lightweight flywheel ring gears.
Because Mercury Racing produced several starter and flywheel combinations over the years, verifying the flywheel ring gear and tooth count before ordering is essential. This starter is intended only for engines using the 10-tooth left-hand racing system and should not be installed on production Mercury flywheels using 8- or 9-tooth starter drives.
Built for Dock Starts
Competition engines demand fast, reliable starts under extreme operating conditions. The ARCO 5384 is engineered to provide consistent cranking torque while withstanding the vibration, heat, and repeated starting cycles common in professional racing.
Its heavy-duty internal construction helps deliver reliable engagement with lightweight racing flywheels while minimizing wear to the starter drive and flywheel ring gear.
Whether starting on the launch ramp, in the pits, or between heats, dependable starter performance is critical for race-day reliability.
Installation Considerations
Before installing the starter, inspect the flywheel ring gear for damaged or worn teeth and verify that the engine is equipped with a left-hand lightweight racing flywheel utilizing the proper 10-tooth engagement pattern.
Battery cables, engine grounds, and the starter solenoid should also be inspected to ensure full battery voltage reaches the starter during cranking.
Because this starter is designed exclusively for Mercury Racing left-hand applications, it should never be substituted for production Mercury starters using different Bendix drives or rotation requirements.
Buckshot Racing #77 Tech Tip
Many starting issues are caused by voltage loss rather than the starter itself. Always load-test the battery, inspect battery cables for corrosion, verify proper grounding, and measure voltage at the starter during cranking before replacing electrical components.
Proper cable size and clean electrical connections are especially important on high-compression Mercury Racing engines.
Final Thoughts
The ARCO 5384 Left-Hand Starter Motor is the correct replacement for Mercury OEM 50-60594T01, 50-60594A1, and 50-60594A used on Mercury Racing's legendary left-hand V6 competition engines. Designed for SST-120, SST-140, Champ, Formula One, S3000, and other 2.0L, 2.4L, and 2.5L left-hand counter-rotating Mercury Racing outboards, it features the correct 10-tooth Bendix drive for OEM and aftermarket billet left-hand flywheels.
For racers and engine builders maintaining these iconic Mercury Racing engines, the ARCO 5384 delivers the dependable cranking performance and precise fit required for professional competition.
Contact Mike Hill with any questions at +1-714-697-1716 or mike@buckshotracing77.com